Vehicle condition responsive monitoring system

ABSTRACT

Apparatus for providing information as to a plurality of conditions using a single air core gauge. Each condition being monitored controls a switch that in turn controls the energization of at least one winding, the magnetic fields generated by the windings forming a resultant magnetic field that controls the orientation of an indicia-bearing rotatable disc. When one or more windings are energized a lamp illuminates the indicia that is located at a certain position by the disc so as to indicate the status of the condition which caused energization of the winding. A steering diode network permits the monitoring of more conditions than the number of windings employed in the gauge. A warning network provides an immediate indication of a change in a condition being monitored regardless of the position of the rotatable disc.

United States Patent Fales 51 May 2,1972

5'41 VEHICLE CONDITION RESPONSIVE MONITORING SYSTEM Douglas 1. Fales,rum, Mich.

General Motors Corporation, Detroit, Mich.

[221 Filed: Nov. 20, 1970 [21] App1.No.: 91,491

[72] Inventor:

[73] Assignee:

[52] U.S. Cl .;....340/52 F, 340/181 [51] ..G08b 19/00 [58] Field ofSearch ..340/52, 52 F, 177, 181, 195,

[56] References Cited UNITED STATES PATENTS Stewart..... Ziegler..340/177 Primary Examiner-Alvin H. Waring Attorney-J. L. Carpenter andPaul Fitzpatrick [57] ABSTRACT I Apparatus for providing information asto a plurality of conditions using a single air core gauge. Eachcondition being monitored controls a switch that in turn controls theenergization of at least one winding, the magnetic fields generated bythe windings forming a resultant magnetic field that controls theorientation of an indicia-bearing rotatable disc. When one or morewindings are energized a lamp illuminates the indicia that is located ata certain position by the disc so as to indicate the status of thecondition which caused energization of the winding. A steering diodenetwork permits the monitoring of more conditions than the number ofwindings employed in the gauge. A warning network provides an immediateindication of a change in a condition being monitored regardless of theposition of the rotatable disc.

4 Claims, 6 Drawing Figures PATENTED 2 972 SHEET 1 0F 2 INVEN'YPli.flmg/asZ/c/es BY E A T TOPNEY PATENTEDMAY 2 I972 3, 660. 8 1 4 sum 2 [F2 IN VENTOR,

VEHICLE CONDITION RESPONSIVE MONITORING SYSTEM This invention relates toapparatus which advises as to the status of a plurality of conditions atvarious remote locations and, more particularly, to motor vehiclesystems for monitoring a plurality of conditions at various remotelocations in a motor vehicle and for indicating the status of theconditions being monitored. This invention also relates to my copendingUS. applications, Ser. Nos. 91,490 and 91,393 which were both filed onNov. 20, 1970 and assigned to the assigneeof this invention.

Many warning systems for advising of conditions in a motor vehicle arepresently in widespread use. These systems may, for example, be employedto monitor fuel level in a gas tank, coolant level in a radiator, oilpressure in an engine crankcase, or the charging of a battery by anelectrical generating system. Generally these prior systems are of twotypes: they either provide a continuous indication of the conditionbeing monitored, the well-known fuel gauge being one example, or theyadvise the vehicle occupant only of a condition which has changed tosuch an extent as to need his attention, as is the case with lamps whichare employed as tell-tales. In either event these systems have had tocompete for space with many other devices which must also be located ina vehicle dashboard so as to be within reach and observation of thevehicle operator. Since the motoring public is provided an opportunityto enjoy an ever-increasing number of comfort and convenience featuresoffered by vehicle manufacturers, the space limitations in vehicledashboards are continuously becoming more acute.

Accordingly, it is an object of this invention to provide apparatuswhich monitors a large number of conditions in a motor vehicle and whichemploys a single dashboard unit to convey information regarding thevarious monitored conditions to the vehicle operator.

A further object of this invention is the implementation of a single aircore gauge to monitor a plurality of conditions at various locations ina motor vehicle.

Another object of this invention is the provision of an air core gaugewhich indicates a plurality of conditions in a motor vehicle and whichonly provides an affirmative indication as to the status of themonitored conditions which the attention of the vehicle operator to oneor more of the conditions is required.

It is a further object of this invention to provide an air core gaugefor monitoring a plurality of conditions which exceed in number thenumber of gauge windings employed in the air core gauge withoutrequiring duplication of sensing devices.

It is yet another object of this invention to provide a single air coregauge which monitors a plurality of conditions and which immediatelyadvises the vehicle operator when one of the conditions being monitoredrequires his immediate attennon.

The satisfaction of the foregoing objects and the advantages of thesubject invention will be apparent from the accompanying description anddrawings, in which:

FIG. 1 depicts an air core gauge of the prior art which may be employedin practicing the subject invention.

FIG. 2 is a perspective view, with parts broken away, of an indicatorembodying the principles of the subject invention.

FIG. 3 is a cross-sectional view of the indicator in FIG. 1.

FIG. 4 is a schematic representation of an indicator circuit accordingto the principles of the subject invention.

FIG. 5 is a modification of the indicator circuit in FIG. 4 having anincreased capacity.

FIG. 6 is a modification of the indicator circuit in FIG. 4 having aprovision for providing the vehicle operator with immediate warnings ofmalfunctions.

Referring now to the drawings, FIG. 1 shows an air core gauge of thetype disclosed in Ziegler, U.S. Pat. No. 3,302,l9l, which may beemployed in practicing the subject invention. As shown in FIG. 1, thegauge 10 includes a winding support member 12 on which are disposedfirst and second coils 14 and 16. The first coil 14 includes a first setof coaxial windings 18 and 20 and the second coil includes a second setof coaxial windings l9 and 21, the windings 18 through 20 in the coils14 and 16 being positioned and wound so as to generate magnetic fieldswhen energized that oppose each other. The winding support member 12supports the coils 14 and 16 so that their respective axes aresubstantially at to each other, which causes the magnetic fieldsproduced by the windings 18 through 21 to combine in a resultantmagnetic field in which the magnetic fields of the opposed windings arecancelled when the opposed windings are equally energized. In addition,the gauge 10 also includes a permanent magnet armature 22 rotatablysupported by a shaft 24 that is restrained in a guideway 26.

As shown in FIGS. 2 and 3, an indicator 28 according to the preferredand illustrated embodiment includes the gauge 10 of FIG. 1 disposed withthe shaft 24 vertical and drivably connected to a rotatable disc 30,which has a depending edge 32 so as to rotate the disc 30 in accordancewith the energization of the windings 18 through 21. A plurality ofwindows 34 through 37 which bear indicia are disposed on the dependingedge 32 of the disc 30 so as to be aligned with a light source, such asa lamp 38, that is mounted in a shroud 40 behind the depending edge 32of the disc 30. The lamp 38 and the winding support member 12 are heldin a fixed relative position by suitable supporting apparatus, such as abracket 42 illustrated in FIG. 3.

Accordingly, as a condition which is being monitored effects a change inthe energization of the windings 18 through 21 the corresponding changein the resultant magnetic field causes the armature 22 to rotate to anew position in which one of the windows 34 through 37 and the indiciawhich it bears is aligned with the lamp 38. Upon energization of thelamp 38 the window is illuminated by the lamp 38 and the vehicleoccupant is made aware of the change in the condition being monitored.

For example, if it is assumed that the lamp 38 and the windings 18through 21 are all normally deenergized and that one of the windings 18through 21 is responsive to the temperature of the vehicle engine .thelamp 38 is normally deenergized and the vehicle operator is thereforenot affirmatively advised of any malfunction of the conditions beingmonitored in the vehicle. That is, so long as the lamp 38 remainsdeenergized he may assume that the conditions being monitored arefunctioning normally. However, should the engine temperature exceed apredetermined level the winding with which it is associated will beimmediately energized and at a predetermined time after the winding isenergized the lamp 38 will be energized, as will subsequently beexplained. Accordingly, the disc 30 is first rotated so as to align thewindow 36, on which is the indicia HOT, with the lamp 38 and then thelamp 38 is energized. Upon energization of the lamp 38 the vehicleoperator is advised of the overheated condition of the engine.

A control circuit 44 for controlling the energization of the windings 18through 21 and the lamp 38 is schematically illustrated in FIG. 4. Asshown in FIG. 4, several detection networks 46 through 49 are providedfor monitoring various conditions in a vehicle. Each detection network46 through 49 includes one of a plurality of normally open switches 50through 53 connected in series with one of the respective windings 18through 21. Power is supplied to the windings 18 through 21 by asuitable power source, such as a vehicle battery 54, through a powerswitch, such as a vehicle ignition switch 56, in accordance with thesetting of the switches 50 through 53. A resistor 58 is connected inseries with the windings 18 through 21 and the battery 54 so as to forma voltage divider in which the common junction 60 of the windings 18through 21 undergoes a wide voltage excursion in accordance with theenergization of the windings 18 through 21, the voltage excursion beingsensed by a PNP transistor 62.which controls the energization of thelamp 38.

So long as all the switches 50 through 53 are open substantially theentire voltage of the battery 54 is applied through the ignition switch56 and the resistor 58 to the common junction 60 of the windings 18through 21. Accordingly, the base 64 of the transistor 62, which isconnected to the junction 60, is at substantially the same voltage asthe emitter 66 of the transistor 62 so the transistor 62 is biased toits nonconductive condition. The transistor 62 thus normally preventsenergization of the lamp 38, which is in series with the collector 68 ofthe transistor 62.

However, should one of the switches 50 through 53, such as the switch52, be closed due, for example, to an overheated engine, the junction 60of the windings 18 through 21 would be at a relatively low potentialthat is established by the voltage divider action of the resistor 58 inseries with the winding 20. Since the resistance of the winding 20 isrelatively small, the base 64 of the transistor 62 would thus be at amuch lower voltage than, the emitter 66 and the forward biasedbaseemitter junction of the transistor 62 makes the transistor 62conductive so as to energize the lamp 38. Accordingly, the energizationof the winding 20 causes the disc 30 to be rotated so as to align thewindow 36 with the lamp 38 and the energization of the lamp 38illuminates both the window 36 and the indicia which it contains so asto advise the vehicle operator that the overheated engine needs hisattention.

It should be noted that the time constant fonned by the resister 58 andone of the windings 18 through 21 when the corresponding switch of theswitches 50 through 53 is closed provides a valuable time delay in theoperation of the indicator 28. Since the disc 30 in all probability isnot aligned with the lamp 38 for a proper indication the moment one ofthe switches 50 through 53 is closed, the disc 30 begins to rotate assoon as one of the windings 18 through 21 is energized. If the lamp 38also were immediately energized when one of the windings 18 through 21becomes energized the indicator 28 may give an initial indication thatis erroneous due to the motion of the disc 30. Accordingly, the windings18 through 21 and the resistor 58 are selected so that the voltage atthe junction 60 is decreased at a sufficiently slow rate when one of theswitches 50 through 53 is closed as to introduce a certain time delayinto the central circuit 44.

By properly selecting the windings 18 through 21 and the resistor 58 thejunction 60 voltage is maintained at a sufficiently high voltage as tomaintain the transistor 62 nonconductive until an energized winding hasaligned the disc 30 for a proper indication of the malfunction. The disc30 is thus always properly aligned before the lamp 38 is energized. Aspersons versed in the art will appreciate, various other time delaycircuitry could also be employed to further delay the energization ofthe lamp 38 after closure of one of the switches 50 through 53. Indeed,the lamp 38 may be selected to be of a type in which the lamp is notilluminated for a certain time after the lamp is energized. A slow lamp,as these lamps are sometimes called, would preclude false indications bythe indicator 28 before the disc 30 is properly aligned and wouldtherefore eliminate the need for additional time delay apparatus.

In the embodiment illustrated in FIG. 5 several diode networks 70through 73 and normally open supplemental switches 74 through 77 thatare responsive to various conditions in the vehicle have been added tothe control circuit 44 of FIG. 4. The diode networks 70 through 73 arecomprised of steering diodes 78 through 85, two of the steering diodes78 through 85 that have their cathodes connected together being includedin each of the diode networks 70 through 73. The supplemental switches74 through 77 are connected to the cathodes of the steering diodes 78through 85 so as to provide for energizing two of the windings 18through 21 upon closure of any one of the supplemental switches 74through 76, as contrasted to the energization of only one of thewindings 18 through 21 upon closure of one of the primary switches 50through 53.

Assume, for example, that the supplemental switch 75 is responsive toengine oil pressure in the vehicle and is closed 4. I stantially at thepotential of the battery 54 and the indicator lamp 38 remainsdeenergized. Since the indicator 28 is not affirmatively providing thevehicle operator with an indication of the malfunction he may properlyassume that all of the systems being monitored are operatingsatisfactorily.

However, should the engine oil pressure fall below the certain level thesupplemental switch 75 closes so as to cause energization of the winding19 through the diode and energization of the winding 20 through thediode 81. Accordingly, closure of the supplemental switch 75 causessimultaneous energization of the windings 19 and 20 so as to generate aresultant magnetic field which is oriented in a direction whichpositions the disc 30 between the positions which the disc 30 wouldadopt if either of the windings 19 or 20 were energized alone.Similarly, closing one I of the other supplemental switches 74, 76, or77 results in energizing two of the windings 18 through 21. Since onlyone of the windings 18 through 21 is energized when one of the primaryswitches 50 through 53 is closed, it is apparent that closing any one ofthe primary switches 50 through 53 or supplemental switches 74 through77 results in the disc 30 being placed in a unique position. It is thusapparent that the control network 44 in FIG. 5 provides eight uniquepositions of the disc 30 and can therefore be used to monitor eightconditions in a vehicle for malfunctions while requiring only the fourwindings 18 through 21 to indicate to the vehicle operator when amalfunction occurs. Accordingly, the control circuit 44 in FIG. 5 allowsthe indicator 28 to be very compact and built according to a lessexpensive design than would be required if a different winding had to beenergized when each of the eight conditions being monitored suffered amalfunction.

In FIG. 6 the control circuit 44 of FIG. 4 has been changed to providean immediate warning to the vehicle operator when certain conditionsoccur in the vehicle regardless of the time required for the lamp 38 tobe energized in the fashion previously explained. These warnings areprovided by a first telltale network 86 comprising a first lamp 87 and afirst steering diode 88 and a second telltale network 89 comprising asecond lamp 90 and a second and .third steering diodes 91 and 92.

In FIG. 6 closure of the switch 52 due to a change in the conditionbeing monitored by the switch 52, such as the temperature of a vehicleengine, effects energization of the winding 20 and, after thepredetermined time delay, energization of the lamp 38 to indicate thechange in the condition being monitored, as previously explained. Inaddition, closure of the switch 52 completes a current path from thebattery 54 through the ignition switch 56, a lead 93, the first lamp 87,and the first steering diode 88. The first lamp 87 is thus immediatelyenergized upon closure of the switch 52 so as to place the driver of thevehicle on notice of an unusually serious malfunction existing in thevehicle. The vehicle operator is therefore immediately advised by theenergization of the first lamp 87 that a serious malfunction exists inthe vehicle though the precise nature of the malfunction is not conveyedto him until the lamp 38 is energized so as to illuminate the disc 30.As previously discussed, the illumination of the lamp 38 is brieflydelayed until the disc 30 is properly aligned by either employing timedelay circuitry, such as the RI. timing network formed by the resistor58 and the windings 18 through 21, or a slow lamp as the lamp 38. Ineither case, an immediate notice of the type provided by the first lamp87 may be especially useful when the engine oil pressure has decreasedbelow a safe level as continued operation of the engine without properoil pressure may result in serious damage to the engine.

Similarly, closing either of the switches 50 or 51 causes energizationof the second lamp 90 through the corresponding second or third steeringdiode 91 or 92. Since the second lamp 90 may be energized upon closureof either of the switches 50 or 51 it may be desirable for the secondlamp 90 to be placed on the vehicle dashboard and labeled as being animmediate warning regarding a single system in which the switches 50 and51 monitor two conditions. The second lamp 90 will thus immediatelyindicate a malfunction of the system. Closing one of the switches 50 or51 also effects energization of the corresponding winding 18 or 19,causing the disc 30 to assume a unique position relative to the lamp 38.accordingly, when the lamp 38 is subsequently illuminated after theaforedescribed time delay a subsequent indication as to the precise typeof malfunction which has occurred in the system is provided by theindicator 28.

It is thus apparent that the apparatus herein described advises avehicle operator of malfunction in any of a large number of systems thatare being monitored, though persons versed in the art will appreciatethat many modifications of this apparatus in addition to those hereindescribed may be made without departing from the spirit of thisinvention.

What is claimed is:

1. Apparatus for indicating the status of a plurality of conditionscomprising, in combination, a plurality of switches each responsive toat least one of the conditions being monitored, each of the switchesnormally being in a first operative state and being changed to a secondoperative state upon a predetermined change in the condition beingmonitored by the switch, a plurality of windings each connected inseries with one of theswitches to form a detection network and effectivewhen energized to produce a magnetic field along the axis of thewinding, the axes of the windings being aligned at predetermined anglesto each other whereby the magnetic fields generated by the windings forma resultant magnetic field the orientation of which varies in accordancewith the energization of the windings, means connecting the detectionnetworks in parallel, means for connecting the detection networks to apower source effective upon placement of a switch in the secondoperative state to cause the energization by the power source of thewinding in series circuit with the switch, indicating means forindicating the status of the conditions being monitored, the indicatingmeans including an indicia bearing member, means for moving the indiciabearing member past a certain position in accordance with theorientation of the resultant magnetic field, a lamp for illuminating theindicia at the certain position, means responsive to the energization ofthe windings effective to energize the lamp when a winding is energizedand deenergize the lamp when the windings are deenergized whereby achange in the status of a certain condition being monitored efiectsillumination of predetermined indicia at the certain position, and timedelay means for preventing the lamp from being energized for apredetermined time after winding has been energized so as to prevent thelamp from illuminating indicia other than that indicative of the changedstatus of the certain condition.

2. Apparatus for indicating the status of a plurality of conditionscomprising, in combination, a plurality of switches each responsive toat least one of the conditions being monitored, each of the switchesnormally being in a first operative state and being changed to a secondoperative state upon a predetermined change in the condition beingmonitored by the switch, a plurality of windings each connected inseries with one of the switches to form a detection network andeffective when energized to produce a magnetic field along the axis ofthe winding, the axes of the windings being aligned at predeterminedangles to each other whereby the magnetic fields generated by thewindings form a resultant magnetic field the orientation of which variesin accordance with the energization of the windings, means connectingthe detection networks in parallel, a resistor, means for connecting thedetection networks in series with the resistor and a power sourceeffective upon placement of a switch in the second operative conditionto cause the energization by the power source of the winding in seriescircuit with the switch, and indicating means for indicating the statusof the conditions being monitored, the indicating means including apermanent magnet armature rotatably positioned so as to be self-aligningwith the resultant magnetic field, a disc drivably coupled to thearmature for movement therewith, the disc having indicia disposedthereon so as to be movable past a certain position in accordance withthe orientation of the armature, the disc positioning predeterminedindicia at the certain position in accordance with the energization ofthe windings and closure of the switches, a lamp for illuminating theindicia at the certain position, a transistor that is series connectedwith the power source and the lamp and responsive to the potentialbetween the detection networks and the resistor so as to be responsiveto the energization of the windings, thereby effecting energization ofthe lamp when a winding is energized and deenergization of the lamp whenthe windings are deenergized whereby a change in the status of a certaincondition being monitored effects illumination of predetermined indiciacorresponding to the certain condition at the certain position.

3. Apparatus for indicating the status of a plurality of conditionscomprising, in combination, a plurality of switches responsive to atleast one of the conditions being monitored, each of the switchesnormally being in the first operative state and being changed to asecond operative state upon a predetermined change in the conditionbeing monitored by the switch, a plurality of windings of a lessornumber than the switches, each winding being connected in series withone of the switches to form a detection network and effective whenenergized to produce a magnetic field along the axis of the winding, theaxes of the windings being aligned at predetermined angles to each otherwhereby the magnetic fields generated by the windings combine to form aresultant magnetic field the orientation of which varies in accordancewith the energization of the windings, means connecting the detectionnetworks in parallel, means for connecting the detection networks to apower source efiective upon closure of the switch in a detection networkto cause the energization by the power source of the winding in seriescircuit with the switch. at least one diode network, each diode networkincluding at least two diodes each of which has an anode connected tothe series circuit connection between the winding and the switch inrespective detection networks and a cathode connected to a switch thatis not part of a detection network and is effective when placed in thesecond operative condition to cause energization of the windings in thedetection networks to which it is connected by diodes, thereby orientingthe resultant magnetic field between the axes of the energized windings,and indicating means for indicating the status of the conditions beingmonitored, the indicating means including an indicia bearing member,means for moving the indicia bearing member past a certain position inaccordance with the orientation of the resultant magnetic field, a lampfor illuminating the indicia at the certain position, and meansresponsive to the energization of the windings effective to energize thelamp when a winding is energized and deenergize the lamp when thewindings are deenergized whereby a change in the status of a certaincondition being monitored effects illumination of predetermined indiciaat the certain position.

4. Apparatus for indicating the status of a plurality of conditionscomprising, in combination, a plurality of switches each responsive toat least one of the conditions being monitored, each of the switchesnormally being in a first operative state and being changed to a secondoperative state upon a predetermined change in the condition beingmonitored by the switch; plurality of windings each connected in serieswith one of the switches to form a detection network and effective whenenergized to produce a magnetic field along the axis of the winding, theaxes of the windings being aligned at predetermined angles to each otherwhereby the magnetic fields generated by the windings form a resultantmagnetic field the orientation of which varies in accordance with theenergization of the windings; means connecting the detection networks inparallel; means for connecting the detection networks to a power sourceeffective upon closure of a switch to cause the energization by thepower source of the winding in series circuit with the switch;indicating means for indicating the status of the conditions beingmonitored, the indicating means including an indicia bearing member,means for moving the indicia bearing member past a certain position inaccordance with the orientation of the resultant magnetic field, a

lamp for illuminating the indicia at the certain position, and

means responsive to the energization of the windings efl'ective toenergize the lamp a predetermined time after a winding is energized anddeenergize the lamp when the windings are deenergized whereby a changein the status of a certain condition being monitored effectsillumination of predetermined indicia at the certain position after thepredetermined time has

1. Apparatus for indicating the status of a plurality of conditionscomprising, in combination, a plurality of switches each responsive toat least one of the conditions being monitored, each of the switchesnormally being in a first operative state and being changed to a secondoperative state upon a predetermined change in the condition beingmonitored by the switch, a plurality of windings each connected inseries with one of the switches to form a detection network andeffective when energized to produce a magnetic field along the axis ofthe winding, the axes of the windings being aligned at predeterminedangles to each other whereby the magnetic fields generated by thewindings form a resultant magnetic field the orientation of which variesin accordance with the energization of the windings, means connectingthe detection networks in parallel, means for connecting the detectionnetworks to a power source effective upon placement of a switch in thesecond operative state to cause the energization by the power source ofthe winding in series circuit with the switch, indicating means forindicating the status of the conditions being monitored, the indicatingmeans including an indicia bearing member, means for moving the indiciabearing member past a certain position in accordance with theorientation of the resultant magnetic field, a lamp for illuminating theindicia at the certain position, means responsive to the energization ofthe windings effective to energize the lamp when a winding is energizedand deenergize the lamp when the windings are deenergized whereby achange in the status of a certain condition being monitored effectsillumination of predetermined indicia at the certain position, and timedelay means for preventing the lamp from being energized for apredetermined time after winding has been energized so as to prevent thelamp from illuminating indicia other than that indicative of the changedstatus of the certain condition.
 2. Apparatus for indicating the statusof a plurality of conditions comprising, in combination, a plurality ofswitches each responsive to at least one of the conditions beingmonitored, each of the switches normally being in a first operativestate and being changed to a second operative state upon a predeterminedchange in the condition being monitored by the switch, a plurality ofwindings each connected in series with one of the switches to form adetection network and effective when energized to produce a magneticfield along the axis of the winding, the axes of the windings beingaligned at predetermined angles to each other whereby the magneticfields generated by the windings form a resultant magnetic field theorientation of which varies in accordance with the energization of thewindings, means connecting the detection networks in parallel, aresistor, means for connecting the detection networks in series with theresistor and a power source effective upon placement of a switch in thesecond operative condition to cause the energization by the power sourceof the winding in series circuit with the switch, and indicating meansfor indicating the status of the conditions being monitored, theindicating means including a permanent magnet armature rotatablypositioned so as to be self-aligning with the resultant magnetic field,a disc drivably coupled to the armature for movement therewith, the dischaving indicia disposed thereon so as to be movable past a certainposition in accordance with the orientation of the armature, the discpositioning predetermined indicia at the certain position in accordancewith the energization of the windings and closure of the switches, alamp for illuminating the indicia at the certain position, a transistorthat is series connected with the power source and the lamp andresponsive to the potential between the detection networks and theresistor so as to be responsive to the energization of the windings,thereby effecting energization of the lamp when a winding is energizedand deenergization of the lamp when the windings are deenergized wherebya change in the status of a certain condition being monitored effectsillumination of predetermined indicia corresponding to the certaincondition at the certain position.
 3. Apparatus for indicating thestatus of a plurality of conditions comprising, in combination, aplurality of switches responsive to at least one of the conditions beingmonitored, each of the switches normally being in the first operativestate and being changed to a second operative state upon a predeterminedchange in the condition being monitored by the switch, a plurality ofwindings of a lessor number than the switches, each winding beingconnected in series with one of the switches to form a detection networkand effective When energized to produce a magnetic field along the axisof the winding, the axes of the windings being aligned at predeterminedangles to each other whereby the magnetic fields generated by thewindings combine to form a resultant magnetic field the orientation ofwhich varies in accordance with the energization of the windings, meansconnecting the detection networks in parallel, means for connecting thedetection networks to a power source effective upon closure of theswitch in a detection network to cause the energization by the powersource of the winding in series circuit with the switch, at least onediode network, each diode network including at least two diodes each ofwhich has an anode connected to the series circuit connection betweenthe winding and the switch in respective detection networks and acathode connected to a switch that is not part of a detection networkand is effective when placed in the second operative condition to causeenergization of the windings in the detection networks to which it isconnected by diodes, thereby orienting the resultant magnetic fieldbetween the axes of the energized windings, and indicating means forindicating the status of the conditions being monitored, the indicatingmeans including an indicia bearing member, means for moving the indiciabearing member past a certain position in accordance with theorientation of the resultant magnetic field, a lamp for illuminating theindicia at the certain position, and means responsive to theenergization of the windings effective to energize the lamp when awinding is energized and deenergize the lamp when the windings aredeenergized whereby a change in the status of a certain condition beingmonitored effects illumination of predetermined indicia at the certainposition.
 4. Apparatus for indicating the status of a plurality ofconditions comprising, in combination, a plurality of switches eachresponsive to at least one of the conditions being monitored, each ofthe switches normally being in a first operative state and being changedto a second operative state upon a predetermined change in the conditionbeing monitored by the switch; plurality of windings each connected inseries with one of the switches to form a detection network andeffective when energized to produce a magnetic field along the axis ofthe winding, the axes of the windings being aligned at predeterminedangles to each other whereby the magnetic fields generated by thewindings form a resultant magnetic field the orientation of which variesin accordance with the energization of the windings; means connectingthe detection networks in parallel; means for connecting the detectionnetworks to a power source effective upon closure of a switch to causethe energization by the power source of the winding in series circuitwith the switch; indicating means for indicating the status of theconditions being monitored, the indicating means including an indiciabearing member, means for moving the indicia bearing member past acertain position in accordance with the orientation of the resultantmagnetic field, a lamp for illuminating the indicia at the certainposition, and means responsive to the energization of the windingseffective to energize the lamp a predetermined time after a winding isenergized and deenergize the lamp when the windings are deenergizedwhereby a change in the status of a certain condition being monitoredeffects illumination of predetermined indicia at the certain positionafter the predetermined time has elapsed; and warning means forproviding an immediate indication of a change in a certain conditionregardless of the position of the indicia bearing member, said warningmeans including an indicating device connected in series with the powersource and the switch that is responsive to the certain conditioneffective to immediately energize said indicating device upon closure ofthe switch.